Tonight, like Thursday night, the 2010 version of the Perseid meteor shower will put on one of its more active displays -- an annual event that reinforces the value of a night sky far removed from artificial light, says an executive of the International Dark-Sky Association.
Johanna Duffek, education liaison for the IDA, a Tucson, Ariz.-based nonprofit, advocates the use of focused, shielded outdoor lighting that reduces the amount of unnatural light that seeps into the night sky and causes "light pollution" -- defined by the IDA as "any adverse effect of artificial light including sky glow, glare, light trespass, light clutter, decreased visibility at night, and energy waste."
Light trespass? Duffek describes it as light "coming into your window from a neighbor's light or a streetlight.
"It can affect your circadian rhythms and sleep patterns, which can affect your health in other ways while you're awake," Duffek says.
Wildlife can also be affected. "Almost all species are affected by too much artificial light at night, especially with the encroachment of development next to parks and preserves. It affects almost all species in terms of predation, mating, migration and more," she says.
"Amphibians don't develop as quickly as they should, which means they have a very small window for mating, so they don't reproduce effectively. Ultimately you lose base predators and prey."
"On top of all that," Duffek adds, "it's just a plain darn waste of energy."
She points out that Calgary, Alb., undertook a streetlight retrofit project, replacing traditional lighting with focused, flat lens fixtures (permitting the use of lower-watt bulbs). The city now rakes in an estimated $1.7 million in annual energy savings.
Most of the IDA's efforts revolve around urban areas, where volunteers work with local governments to enact outdoor lighting ordinances. Yet the group also has an interest in lighting that encroaches on wilderness areas. "It's important to preserve those areas where people camp and hike," Duffek says.
In 2006, the IDA designated Natural Bridges National Monument as the first International Dark Sky Park. Kevin Poe, coordinator of the annual Bryce Canyon Astronomy Festival, says Natural Bridges has a limiting magnitude (a measure of how faint of a star can be viewed by the naked eye) of 7.6, tops in North America.
To get a good look at Perseid activity, which could occur anywhere in the night sky, try watching the northeast sky after midnight in your local area. Perseid activity will gradually decline as August progresses.
Duffek says light pollution deprives 21st century humans of a memorable phenomenon once enjoyed by our ancestors.
"We're in a unique time in history," she says. "More people live in urban areas than in rural areas. So many people are growing up and they've never seen a truly dark sky where the Milky Way simply glows in the heavens. They've never witnessed that awe. It's not something that they know that they've missed because they've never seen it before. So if they're moving out of an urban area to a rural area, they could be afraid of the dark. That's a shame."